package com.yin.myproject.netty.demo05;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

/**
 * @author Eason
 * @create 2017-12-11 23:18
 **/
public class MultiplexerTimeServer implements Runnable {


    private Selector selector;
    private volatile boolean stop;

    /**
     * 初始化多路复用器
     * 1.初始化ServerSocketChannel
     * 2.创建并启动线程selector
     * 3.设置ServerSocketChannel为非阻塞模式
     * 4.将ServerSocketChannel注册到Selector监听
     *
     * @param port
     */
    public MultiplexerTimeServer(int port) {
        try {
            selector = Selector.open();
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
            serverSocketChannel.configureBlocking(false);
            serverSocketChannel.socket().bind(new InetSocketAddress(port));
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            System.out.println("The nio server start in port : " + port);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void stop() {
        this.stop = true;
    }

    @Override
    public void run() {
        try {
            while (!stop) {
                selector.select(1000);
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                SelectionKey key;
                Iterator<SelectionKey> iterator = selectionKeys.iterator();
                while (iterator.hasNext()) {
                    key = iterator.next();
                    iterator.remove();
                    try {
                        hadleInput(key);
                    } catch (IOException e) {
                        if (key != null) {
                            key.cancel();
                            if (key.channel() != null) {
                                key.channel().close();
                            }
                        }
                    }
                }
            }
            //多路复用器关闭后，所有注册在上面的Chaanel和Piple等资源都会被自动去注册并关闭，所以不需要重读释放资源
            if (selector != null) {
                selector.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 处理客户端接入
     *
     * @param key
     * @throws IOException
     */
    private void hadleInput(SelectionKey key) throws IOException {
        if (key.isValid()) {
            //处理接入的请求信息
            if (key.isAcceptable()) {
                //Accept the new connection
                ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
                SocketChannel sc = ssc.accept();
                sc.configureBlocking(false);
                //Add the new connection to the selector
                sc.register(selector, SelectionKey.OP_READ);
            }
            if (key.isReadable()) {
                //Read the data
                SocketChannel sc = (SocketChannel) key.channel();
                ByteBuffer readBuffer = ByteBuffer.allocate(1024);
                int readBytes = sc.read(readBuffer);
                if (readBytes > 0) {
                    readBuffer.flip();
                    byte[] bytes = new byte[readBuffer.remaining()];
                    readBuffer.get(bytes);
                    String body = new String(bytes, "UTF-8");
                    System.out.println("The time server receive content : " + body);
                    doWrite(sc, "response :" + body);
                } else if (readBytes < 0) {
                    key.cancel();
                    sc.close();
                } else {
                    //读到零字节，忽略
                }
            }
        }
    }

    /**
     * 响应客户端
     *
     * @param channel
     * @param response
     * @throws IOException
     */
    private void doWrite(SocketChannel channel, String response) throws IOException {
        if (response != null && response.trim().length() > 0) {
            byte[] bytes = response.getBytes();
            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
            writeBuffer.put(bytes);
            writeBuffer.flip();
            channel.write(writeBuffer);
        }
    }


}
